1. Field of the Invention
The present invention generally relates to an image processing apparatus, an image processing method and a navigation apparatus, which can obtain a distance to a road edge and a road width on the basis of an image signal from an image-taking device (e.g., a motion picture camera) in a vehicle, which is presently traveling. The present invention also relates to a program storage device for storing a program and a computer data signal embodied in a carrier wave, which enable a computer to function as such an image processing apparatus.
2. Description of the Related Art
There is a navigation apparatus, which detects a present position of a vehicle as a movable body, and displays the detected present position together with a road map around it, to thereby conduct a route guidance. In this type of the navigation apparatus, a large storage capacity record medium (e.g., a CD-ROM, a DVD-ROM or the like), on which map data are recorded, is equipped, and is used to generate the display data displayed on a display picture plane. The map data on the record medium include data related to the shape of the road and various data for display as well as road width information accompanying those. Therefore, it is possible to read out the road width information corresponding to the road on which the vehicle is presently traveling, and the road width of this road can be grasped.
However, according to the above mentioned navigation apparatus, the road width information included in the map data does not indicate an accurate road width, but indicates an inaccurate and rough road width of the road, such as 5.5 m to 8 m for example. Thus, it is not possible to obtain an accurate road width information finely corresponding to each point of the road. Further, it is desired that the distance to the edge of the road is obtained in a real time manner and is used for the safe driving of the vehicle.